To provide a smooth finish on corners and other intersections of interior and exterior surfaces of buildings and similar structures, it is known to attach a metal or plastic elongated strip along the intersection and to utilize the strip as a guide and support for applying joint compound, stucco or the like. The joint compound may be readily manipulated and formed when wet, and is applied to the strip and the surfaces with various tools (such as trowels, for example) to provide a smooth, asthetically pleasing, finished surface at the corner.
For a number of reasons, substantial skill is required to apply the joint compound in an efficient manner. First, the compound can only be manipulated while it is wet or semi-liquid, and it often dries in a relatively short time span. Second, because it must be applied in its semi-liquid, relatively easily formable state, it is difficult to precisely limit the area of application of the compound. As a result, compound material tends to overflow or spatter onto surfaces adjacent the desired area of application, including other areas of the corneraide strip. If such excess material is not removed or wiped off while in its semi-liquid state, it will harden and must subsequently be removed by sanding or some similarly slow, energy-intensive action.
Thus, it is desirable to provide a corneraide guide which enables stucco or other finishing material to be applied quickly and smoothly and formed into the desired finished shape, while also permitting ready clean-up of any excess finishing material which is inadvertently or unavoidably spattered onto adjacent surfaces. The corneraide of the invention provides substantial improvements over the prior art in this regard.
The cross-sectional configurations of prior art corneraide devices involve inherent shortcomings in connection with the aforementioned criteria. For example, constructions such as U.S. Pat. No. 3,109,207 to Cooper incorporate a basically perpendicular cross-section to cover the intersection of two surfaces. Although smooth finished surfaces and corners may be achieved through the use of such cross-sectional shapes, they incorporate numerous inadequacies.
When joint compound is applied over one of the flange portions of Cooper on one of the surfaces forming the intersection, excess compound tends to spill over onto the other flange portion and surface. Normally, compound is applied to the first flange adjacent the corner bead and subsequently to the adjacent wall surface. The two deposit areas are then fayed and blended into each other to form a smooth surface terminating at the bead.
This "overspill" phenomena also occurs when the compound is subsequently applied to the second flange portion and surface. Unless the person applying the compound has the luxury of being able to allow the first surface to dry before beginning to work on the second surface, the compound on the first surface will still be soft when additional compound is applied to the second surface. Any excess compound from that second-surface application which contacts the still-soft compound on the first surface may mar or otherwise damage the soft areas of the compound on the first surface.
In addition, and as indicated above, it is common to apply the aforesaid joint compound or stucco with a trowel or similar expedient. Moreover, it is common to utilize the trowel for other purposes, including cleaning the excess compound from adjacent surfaces. When employing the edge of a trowel or similar applicator to remove any excess material from the Cooper corneraide, however, great care must be taken to avoid nicking or otherwise denting the exposed corner of the corneraide. Frequently, the necessarily honed edge of the trowel will cut into the corner, requiring remedial measures to achieve the desired smooth finish.
Furthermore, the gypsum wallboard or other surfaces to be finished frequently includes some unintentional non-planar deviations or curvature therein (commonly caused by the non-planarity of the supporting studs or other wall structure), which can be especially noticeable at exposed corners and other intersections where corneraide devices are employed. Corneraides of a construction similar to Cooper have little inherent rigidity with which to maintain a desired linear alignment along the intersection and to so provide an operable guide for finishing the joint. Instead, Cooper-type constructions tend to waver and follow any deviations in the respective surfaces of the intersection. Accordingly, the application of joint compound to the Cooper corneraide also tracks any such undesirable deviations.
Another prior art construction of increasing popularity is known as bull-nose corneraide. It incorporates flangellate portions along each surface of the intersection, similar to Cooper, but also includes a curved intermediate portion along the length of the corneraide, whereby the intersection of the surfaces may be provided with a curved transition from one surface to the other. Even though recently achieving popularity due to its relatively new and modernistic shape, it suffers from many of the same shortcomings as does the Cooper corner strip.
Among other things, it is relatively difficult to remove excess joint compound from the bull-nose curved surface. Even skilled workers utilizing specially designed tools must employ two cleaning passes (one for each surface) to accomplish the necessary cleaning. Those less skilled or without the aforementioned special tools frequently utilize rags or their hands to clean the curvilinear intermediate portion.
In addition, the curvilinear cross-section of bull-nose corneraide requires a substantial backside clearance; that is, the supporting materials which form the intersecting surfaces cannot approach one another too closely or they will contact the curved intermediate portion of the bull-nose corneraide and prevent the operative juxtaposition of the flangellate portions thereof with the intersecting surfaces. Although the necessary clearance may be provided without excessive effort in new structures, it can require extensive labor to "cut-back" corners of existing structures for purposes of remodeling with the bull-nose configuration.
Another difficulty in utilizing the bull-nose construction occurs at the top and particularly the bottom ends of the corners. In many interior environments, a molding, baseboard or similar structure is affixed to walls along the top and/or bottom edges thereof. These moldings and baseboards are typically fabricated from wood or a similarly inflexible material. For standard angular (non-bull-nose) corners, the baseboard material may be readily mitered at an appropriate angle to achieve a smooth transition around the corner.
For bull-nose corners, however, such mitering cannot accomplish the curvature (non-linearity) necessary to approximate the curvature of the bull-nose corner lying therebehind. As a result, unsightly gaps exist at at least some areas between the baseboard and the bull-nose when standard baseboard is utilized.
Furthermore, the exposed curvilinear bull-nose corner is particularly susceptible to denting from ordinary pedestrian traffic and general wear and tear in various environments. Such denting may also occur during the original construction activities during and subsequent to the installation of the bull-nose device. Repairs for such dents are typically made by applying joint compound to the curved surface and shaping and sanding same to achieve the appropriate curvature. Such repairs involve substantial time to effectuate, and the "filler" of compound is prone to "popping out" upon subsequent contact with the bull-nose.
Yet another difficulty with bull-nose corneraide is that its curved surface tends to flatten when the corneraide is cut to an desired length. Tin snips ar typically utilized to cut metallic corneraide. When cutting metal bull-nose corneraide, because of the light-weight metal's lack of "memory" (it does not tend to return to its desired curved cross-sectional configuration), the metal must be reshaped by hand in the area adjacent the cut so that it will approximate the desired curvature.